Spring group



May 17, 1955 T. R. WEBER I 2,708,574

SPRING GROUP Filed April 10, 1952 7Bm/DORE R. WEBER -mvznon `ATTRIIEV United States Patent O SPRING GROUP Theodore R. Weber, Latrobe,

Locomotive Company, tion of New York Pa., assignor to American This invention relates to a spring group ior use in railway vehicle trucks to provide resilient support for the truck bolster upon the side frame.

An object of the invention is to provide a bolster supporting spring group for use in a railway vehicle truck which includes a novel friction absorbing device or snubber to control the spring members of the group in a manner preventing the creation of harmonious and synchronous vibrations of the springs which would result 1n damage to the truck parts and lading. A further object of the invention is to provide such a spring group comprising a nest of springs, a snubber, and associated spring seats wherein the friction elements of the snubber are protected from high frequency vibrations. A further object of the invention is to provide such a spring group having the capacity to compensate for movements of the bolster such as canting, lateral displacement, and unsquaring relative to the truck frame. Still a further object is to provide such a spring group to include a snubber having segmented brake shoes adapted to be spread into frictional engagement with a sleeve anchored to the top spring seat thereby to limit the recoil of the springs.

Still another object is to provide a spring group comprising a plurality of coiled springs in the center of which is arranged a novel snubber unit to limit the recoil of the springs, said snubber unit including a braking sleeve anchored to the top spring seat, a segmented brake shoe resting on a compression spring, an expander to coact with the shoe, and a center bolt to anchor the expander to the bottom spring seat, the unit being so arranged that on the recoil of the coiled springs the snubber compression spring will force the shoe upwardly against the anchored expander which will force it to spread radially to frictionally engage the braking sleeve thereby to snub the recoil of the springs.

Other and further objects of and advantages of the invention will be set forth in the following description and claim.

In the accompanying drawings, Fig. l is a top plan view of the spring group embodying the invention. Fig. 2 is a cross-section taken on the line X--X of Fig. 1 shown with all springs under full compression.

Generally described, the spring group of the invention comprises a nest of four double coil springs with a snubber, generally indicated at 11, disposed centrally of the springs. The group is confined between top and bottom spring seats 12 and 13 which are adapted for engagement respectively with the bolster and side frame of a railway truck.

Described in detail, the spring seats are fabricated of smooth surface pressed steel and are formed with marginal flanges 14 and 15 to confine and accurately locate the springs 10. Top spring seat 12 has a central circular opening 16 (Fig. 1) surrounded by a downwardly or inwardly projecting ange 17 which increases the rigidity of the seat and also serves as a connecting means between the seat and sleeve 18, the latter being welded to the former at 19. Sleeve 18 may be a section of seamless steel tubing and is provided with an internal frictional New York, N. Y., a corporasurface 18a for purposes later described. Bottom spring seat 13 has a centrally located upwardly and inwardly formed housing 20 which provides an outwardly opening recess or inverted well 21 coaxially disposed in relation to the circular opening 16 in the top spring seat. Coils 10 are long travel suspension springs comprising conventional inner and outer coil elements.

Snubber spring 22 is a coil spring positioned in the center of the four suspension springs 10 coaxially with the sleeve 16 (see Fig. l). Spring 22 rests upon spring seat 13 snugly against the base of the side wall 23 of well housing 20 which thus functions to locate the spring in operative position. Resting on the flat ground top end of snubber spring 22 is a cylindrical shoe 24 comprised of three segments (see Fig. l) the periphery of which is provided with a thick covering 25 of high friction material. Shoe 24 is arranged flush against the inside surface of sleeve 18 so that a high frictional or braking engagement will result when said elements rub against each other. Shoe 24 has a central diaphragm 26 which is the means by which the shoe rests upon spring 22. Diaphragm 26 has a central opening, the wall of which tapers downwardly and inwardly to form a wedging surface 27. A wedge expander 28, having a cylindrical portion 29 and a conical portion 30, is positioned within the opening in the shoe diaphragm so that its conical portion 30 rests upon the wedging surface 27 of the shoe. The tapers of portion 30 and of wedging surface 27 are the same so that the shoe and expander are adapted to coact, as hereafter described.

Extending through a central aperture 32 in expander 28, through spring 22, and through an opening 33 in recess wall 23 into recess 21 is a center bolt 35 which serves to clamp expander 28 tightly against shoe 24 and to hold the latter atop spring 22 in operative position against sleeve 18. Stacks of flexible resilient washers 36 and 37 are disposed respectively in a recess 38 in expander 28 and in recess 21. When nut 39 is tightened at the time of the original assembly of the unit, the segmented shoe 24, the expander 28, the snubber coil spring 22, and the washers 36 and 37 are clamped firmly into operative position.l Such clamping action causes the expander to force the segmented shoe radially outward so that its covering 25 engages sleeve 18 to provide frictional opposition to the telescoping movement which takes place between these elements when the spring group is in operation. It should be here observed that there is considerable clearance between the shank of the bolt and the expander and that the opening 33 in well wall 23 is somewhat larger than the diameter of the bolt. It should also here be observed that there is a clearance between each stack of washers and the bolt.

In operation, it will be seen that downward movements of the truck bolster under riding conditions are transmitted through the top spring seat 14 and through coil springs 10 to the bottom spring seat 15 and hence to the truck side frame. A considerable component of such downward force is transmitted through shoe 24 to snubber spring 22 and hence to the truck side frame as the result of the frictional engagement of shoe 24 and sleeve 18. This component is suliicient to substantially counterlact the wedging pressure of spring 22. In this connecradially as required by the taper of wedgng surface 27. Hence a double frictional engagement or braking eect is produced upon the shoe 28. One frictional engagement is between the tapered surfaces of the shoe and the expander and the other is between the shoe periphery and the sleeve. That is to say, the shoe is wedged between the sleeve and expander.

An added advantage of the invented construction is the universal movement allowed the top spring seat 14 relative to the bottom seat 1S. This results from the fact that the center bolt 35 is permitted a pivotal movement about its lower end. As has been pointed out, considerable clearance exists between the bolt shank and the lower stack of washers 37 and between the bolt shank and the well wall 23. Likewise there is clearance between the bolt shank and the expander 24 and between the shank and the upper stack of washers 36.

While there has been hereinbefore described an approved embodiment of this invention, it will be understood that many and various changes and modifications in form, arrangement of parts and details of construction thereof may be made without departing from the spirit of the invention, and that all such changes and modifications as fall within the scope: of the appended claim are contemplated as a part of this invention.

What I claim is:

A spring group for a railway vehicle truck comprising a plurality of suspension springs; a bottom spring seat; a top spring seat having a sleeve with a friction surface thereon', a segmented shoe having a peripheral friction surface engaging the sleeve friction surface, a central ange normal to the axis of the sleeve, and a frustoconical friction surface on the central flange defining a central opening; an expander having a frusto-conical peripheral friction surface engaging the like friction surface of the shoe and a central opening registering with the central opening of the shoe; a coil compression spring disposed on the bottom spring seat to engage the central flange of the shoe to support the latter; a bolt loosely extending through the registered openings of the shoe pander normally to force the segmented shoe radially into engagement with the sleeve friction surface whereby the shoe is wedged between the sleeve and the expander to produce a snubbing effect whenever the shoe moves axially within the sleeve toward the top spring seat.

References Cited in the le of this patent Y UNITED STATES PATENTS 1,169,862 Peycke Feb. 1, 1916 2,059,503 Webb Nov. 3, 1936 2,155,451 Sproul Apr. 25, 1939 2,319,606 Krautheim May 18, 1943 2,398,749 `Light Apr. 16, 1946 2,479,863 Pierce Aug. 23, 1949 

